Enhancement for 'ajax' form class: submit buttons behave more like normal submissions...

Enhancement for 'ajax' form class: submit buttons behave more like normal submissions, submitting their name/values through a hidden field.

This should work well for simple cases, but could conceivably create false positives if there's a click handler on the specific buttons, depending on whether event processing passes it on. Double-check if you're doing such forms along with the 'ajax' class!